1. Field of the Invention
The present invention relates to an image processing apparatus.
2. Description of the Related Art
Detecting the resolution of an input image and automatically correcting the image is a known art. In U.S. Pat. No. 7,664,335 (Japanese Patent Application Publication No. 2006-166188), for example, Kurumisawa et al. describe an automatic image correction circuit that detects the resolution of an image by counting clock periods during the interval from the rise to the fall of an image data enable signal. The automatic image correction circuit then selects image correction parameters and calculates settings based on the detected resolution, and performs an image correction based on the selected parameters and calculated settings.
Counting clock periods during an image data enable signal is equivalent to counting pixels in the horizontal direction or scanning lines in the vertical direction. In effect, the resolution of the input image is detected from its horizontal and vertical pixel counts. A problem is that these pixel counts do not always reflect the actual resolution of the image. In particular, if the image is an enlarged version of a low-resolution image, its actual resolution is lower than the resolution indicated by the pixel counts. An image of this type cannot be processed correctly if it is corrected on the basis of its pixel counts.